The present invention relates to the handling of signatures that are delivered from a printing press. It relates particularly to a system in which signatures delivered from the press are formed into stacks, and the stacks are then clamped by a transfer vehicle and transported by the transfer vehicle to a delivery station.
Signatures that are delivered from a printing press are typically formed into stacks, and the stacks are then transported to a tying station where they are tied into logs. If it is desired, end boards may be associated with the stack before it is tied. After the stacks of signatures are tied, they can be loaded onto pallets, taken to a storage location, and later removed from the storage location and delivered to an assembling station where they are collated into magazines and other publications.
In transporting stacks of signatures from a stacking station to a tying station, it is known to use a conveyor. It is also known to use a fork lift truck. However, neither of those techniques maintains a positive clamping of the stack of signatures as it is being transported between the stations. Thus, there is a possibility for the stack to become disarrayed as it is being transported. That problem becomes particularly acute where it is desired to operate the conveyor or the fork lift truck at a high rate of speed.
An alternative to conveying stacks of signatures from a stacking station to a tying station is to provide a separate tying station for each stacking station. However, for printing presses with multiple deliveries, which is common, that alternative is expensive. Also, it requires that each stacking station be designed to handle the situation where the typing station associated with that stacking station fails. Otherwise, failure of one tying station could necessitate shutdown of the entire printing press.